Angels are forms, images and expressions through which the essences and energy forces of God can be transmitted; and, since there are an infinite number of these forms, the greatest service anyone can pay the angelic host is never consciously to limit the ways angels might appear to us.
Gratitude is the most fruitful way of deepening your consciousness that you are not an "accident", but a divine choice. It is important to realize how often we have had chances to be grateful and not have used them. When someone is kind to us, when an event turns out well, when a problem is solved, a relationship restored, a wound healed, these are very concrete reasons to offer thanks.
What fascinates me so much is that every time we decide to be grateful, it will be easier to see new things to be grateful for. Gratitude begets gratitude, just as love begets love.